Equiv. Parts: 2SD669, 2SB649

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Rarkov

Rarkov

Member
2002-08-30 12:31 pm
North East, UK
www.garethbradley.co.uk
  • #1
    Hi,
    Does anyone know of equivilent part numbers for the following:

    * Hitachi 2SD669
    * Hitachi 2SB649

    BTW, the package is a TO-192...

    Here is a link to the datasheets.

    The circuit designer, Randy Slone, told me that some people replaced them with components from the MJE series but he couldn't remember the part numbers. I believe they are made by motorola but I cannot find any datasheets.

    Any help would be GREATLY appreciated!
    Thanks in advance!!!
    Gaz
     
    S

    soundboy

    Member
    2002-05-17 12:10 pm
    London, UK
  • #6
    have u tried the onsemi website, they seem to have an intuitive competitor cross reference page,
    http://www.onsemi.com/xref/CompetCrossRef/0,4291,,00.html

    the results show mje344 is a suitable substitute for 2sd669 and the mje350 for the 2sb649.

    I'm also very interested in Randy Slone's Mosfet designs, and would like opinions on sound and any mods if any of you out there have built them :)
     
    Rarkov

    Rarkov

    Member
    2002-08-30 12:31 pm
    North East, UK
    www.garethbradley.co.uk
  • #7
    Ah,
    Well done!!! I didn't see that...

    The reason I went for this design is:

    Quote:

    (The Audiophile's Source Book pg172)Finally, we come to Fig. 6-21, which is my favourite audio power amplifier design of any type .

    and I'm sure he's built alot of amplifiers! THD+N is 0.04% but usually more like 0.005% and BW is 3Hz to 120kHz! The SNR is over -115dB...I don't claim to understand what Signal to Noise Ratio is when measured in dB...I thought that a ratio had no units but there you go!

    Anyway...I'll have a look for UK suppliers of the MJE344 and MJE350...

    Thanks
    Gaz
     
    C

    Christer

    Member
    2002-09-19 9:26 pm
    Sweden
  • #8
    Rarkov,

    I have only checked what is available from swedish suppliers, but the closest match I have found are the Toshiba devices 2SA1837
    and 2SC4793, which I think should work fine.

    I recommend against the suggested Motorola/ON devices
    MJE344 and MJE350. Compared to the orignal devices, 2SB649
    and 2SD669, they seem quite inferior.
    1) A min. fT of only 15MHz, compared to 140MHz
    2) Max. IC is 500mA, compared to 1.5A
    3) Wider spread in hFE and much lower min hFE
    4) They seem not even to be complementary devices.
    They would probably work in any of Sloanes amplifiers, but so
    would problably a number of other BJTs having similar specs.

    Why do you want a replacement, BTW? Admittedly 2SB649 and
    2SD669 tend not to show up in every suppliers stock, but
    decent replacements seem at least as rare, in my experience.
    If you search for the part numbers with Altavista or Google, you
    will find quite a number of European suppliers of these devices,
    some of them most certainly in the UK.

    BTW, Spice models for 2SB649 and 2SB669 would be most
    appreciated.
     
    C

    Christer

    Member
    2002-09-19 9:26 pm
    Sweden
  • #12
    Rarkov,

    I have checked a number of different manufacturers compatibility
    recommendations, and they were all questionable.
    The problem is that SB649/SD669 are rather
    special devices and not many manufacturers have something
    similar. It seems that they basically try to find a device that
    is "safe" to use, ie. greater or equal VCE, IC and power rating,
    and do not care much about other properties. Obviously, ON
    does not even make sure that the IC rating is sufficient.

    It will most likely work to use the suggested ON devices in
    any of Sloanes amplifiers, but be prepared that tech. specs.
    and sound quality may be inferior. To what extent is probably
    hard to predict though.

    Anyway, go ahead and use the ON devices if you want to
    give them a try. If it sounds good, be happy, otherwise, try
    to get hold of better devices. Just make sure that you don't
    need the higher IC rating in the particular design your building.
     
    S

    soundboy

    Member
    2002-05-17 12:10 pm
    London, UK
  • #13
    I remember quite a while ago i emailed Randy Slone with the same problem, ie. I couldn't source the Hitachi 2sd669/2sb649 bjt's and his reply was...

    "There isn't anything "super special" about the 2SD669/2SB649 devices. You should be able to obtain equal results from several devices in the "MJE" line - just try to match the Hfe, Ft, and Pd parameters fairly close, and the performance should be equal. "

    (hope Randy doesn't mind me quoting him, hehe)
     
    C

    Christer

    Member
    2002-09-19 9:26 pm
    Sweden
  • #14
    I agree there is nothing "super special" about SB649/SD669
    except the particular combination of essential parameters.
    The problem is to find a close match for all of these. I just
    tried the parametric search at ON semi again, to see if I had
    missed some possible replacement in my earlier searches, but
    it seems I hadn't. Assuming we want a min VCE >= 150V and
    IC >= 500mA, there is only MJE 344 and some similar devices
    for even higher voltages (I only bothered checking for NPNs).

    The most problematic parameter is fT, which is about 10% of
    the value for SD669. I don't know how much difference this
    will make in practice, but it is one of the parameters Sloane
    list as crucial ones for a driver. Also, looking at similar japanese
    devices designed for driver stages, they typically have a high
    fT. I guess this all boils down to the old discussion of how much
    bandwidth is needed in an amplifier. Most certainly there is
    quite a lot of expensive and good-sounding amplifiers on the
    market using drivers similar to MJE344/350.

    Actually, when rechecking my local supplier, I just realized that
    MJE340 seems more similar to MJE350, than MJE344 does. This
    also made me recheck the datasheets and there is no spec. for
    the fT value at all for MJE340/350. That is why I had dismissed
    these devices and forgotten about them.
     
    sam9

    sam9

    Member
    2002-06-26 8:29 pm
    Left Coast
    www.drachen-audio.com
  • #16
    2sd669/2sb649 source

    A: MCM carries these. Or at least it did once. It now appears to be part of Newark -- so who knows?


    B: I built a rather low powered version of one of Slone's amps to squeeze into a small box under my PC monitor to drive a set of small speakers. If you discount my fumblings and goofs, it was quite straight forward. I had access to an older distortion analyzer (measures down to .003%) and was unable to even get a reading in the audible spectrum until 20kHz, --which has been inauible to me for the last couple of decades! I'm working on higher powered version presently.
     
    sam9

    sam9

    Member
    2002-06-26 8:29 pm
    Left Coast
    www.drachen-audio.com
  • #17
    Alternative ? Maybe?

    I just happened to notice the Zetex "Super E-line" page in the Digikey catalog. Going strictly by the basic numbers, some of these could sub for 2sb649/2sd669. However, they are a modified to-92 package which leads me to wonder if there is more at issue than just the basic specs.

    if you need to heatsink them you would need to be a little creative since the package isn't even stanadrd TO-92 - kind of squished flat. Also a little pricey.
     
    E

    EternaLightWith

    Member
    2002-05-14 2:47 am
  • #18
    I think I found good replacements, what sayest thou?

    I agree with other on the board about the MJE series from On- Semi. Looks to be a far stretch.

    How about these replacements from Zetex? They have equivalent SPICE models. :nod:

    Hitachi NPN 2SD669 replacements :
    Zetex ZTX1055A or ZTX1056A

    Hitachi PNP 2SB649 replacements :
    FZT955

    What do you think? All the parameters seem pretty close

    Eternalightwithin

    P.S. For those who don't know that data for these, www.Zetex.com for the Zetex BJTs and Hitachis stuff can be found in the diyaudio archives.
     
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